Note 6 - Employee Benefit Plans - Post-retirement Benefit Obligation to Funded Status and Liability (Details) - Postretirement Health Coverage [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 25, 2021
Accumulated benefit obligation at beginning of year	$ (2,097)	$ (2,398)
Interest cost	(51)	(49)
Actuarial gain	382	241
Benefits paid	109	109
Accumulated benefit obligation at end of year	(1,657)	(2,097)
Plan assets at end of year	0	0
Funded status	$ (1,657)	$ (2,097)